The high-definition multimedia interface (HDMI) is a compact audio/video connector interface for transmitting uncompressed digital streams. The HDMI connects a digital multimedia (or audio/video) source (e.g., a set-top box, a DVD player, a personal computer, a video game console, etc.) to a compatible digital sink, such as a digital television. The HDMI is fully described in the HDMI Specification version 1.4 published on Jun. 5, 2009, incorporated herein by reference in its entirety merely for the useful understanding of the background of the invention.
A HDMI cable is a transport medium including three transition minimized differential signaling (TMDS®) channels utilized to transfer video, audio, and auxiliary data encapsulated in TDMS characters and the transmission is synchronized using a high-frequency clock signal running over a clock channel. The TDMS and clock channels are differential pairs. A HDMI cable also includes the following channels: a display data channel (DDC_SCL and DDC_SDA), a consumer electronics control (CEC), and a hot-plug detect (HPD) signal which originates at the sink. The HDMI interface is implemented using a HDMI cable and connectors, each of which includes 19 pins. A source and sink connectors have the same configuration. Table 1 lists the pins in a type A HDMI connector (either a source or sink).
TABLE 1Pin NumberHDMI Signal1.TMDS_Data2+2.Shield3.TMDS_Data2−4.TMDS_Data1+5.Shield6.TMDS_Data1−7.TMDS_Data0+8.Shield9.TMDS_Data0−10.TMDS_Clk+11.Shield12.TMDS_Clk−13.CEC14.Utility15.SCL16.SDA17.DDC/CEC/Ground18.+5 V19.HPD
DisplayPort™ is a standard that defines a digital display interface of a new digital audio/video interconnect. The DisplayPort is intended to be used primarily between a computer and its display monitor, or a computer and a home-theater system. The DisplayPort standard is fully described in the DisplayPort Specification Version 1.1a published in Jan. 11, 2008, by the video electronics standards association (VESA), incorporated herein by reference in its entirety merely for the useful understanding of the background of the invention.
Transport channels of a DisplayPort interface include a main link, an auxiliary (AUX), and a hot plug detect (HPD). The main link is a unidirectional channel that allows data transfers over up to 4 lanes that carry clock signals in addition to the video/audio streams. Each lane is an AC-coupled differential pair. The auxiliary channel is a bi-directional half-duplex channel that carries control and management information and the HPD channel is used by a sink device to interrupt a source device when a plug is connected or disconnected. The DisplayPort interface is facilitated using a proprietary cable and connectors, each of which includes 20 pins. The DisplayPort cable is a cross cable, i.e., a source and sink connector has a different configuration. Table 2 lists the pins and their signals of source and sink DisplayPort connectors.
TABLE 2DisplayPortDisplayPortPin NumberSinksource1.ML_lane0PML_lane3N2.GNDGND3.ML_lane0NML_lane3P4.ML_lane1PML_lane2N5.GNDGND6.ML_lane1NML_lane2P7.ML_lane2PML_lane1N8.GNDGND9.ML_lane2NML_lane1P10.ML_lane3PML_lane0N11.GNDGND12.ML_lane3NML_lane0P13.Config1Config114.Config2Config215.AUX_CHPAUX_CHP16.GNDGND17.AUX_CHNAUX_CHN18.HPDHPD19.ReturnReturn20.AUX_PWRAUX_PWR
Multimedia interfaces that allow connectivity of both the HDMI and DisplayPort (will be referred hereinafter as a “dual mode connectivity interface”) have been recently developed. Specifically, such interfaces can process data compliant with the HDMI and DisplayPort. However, even if a source or sink device has dual-mode connectivity capabilities, the connection is either through a HDMI or a DisplayPort connector. In the related art there is no physical medium (e.g., a cable), other than HDMI or DisplayPort cables, to connect source and sink devices having different connector types.
Interoperability between HDMI and DisplayPort is defined in the VESA DisplayPort Interoperability Guideline Version 1.1a published on Feb. 5, 2009, which requires a dedicated adapter and a HDMI cable. As illustrated in FIG. 1A, a source device 110 including a dual mode connectivity interface and a DisplayPort connector 160 is connected using an adapter 130 and a HDMI cable 120 to a sink device 140 having a HDMI connector 150. Similar configuration, shown in FIG. 1B, is applied when the sink device 140 includes a dual mode connectivity interface and is connected through the DP connector 160 and an adapter 170 to the source device 110 having a HDMI connector 150. This is the only available interoperability configuration that allows a reliable connection between a HDMI compliant source/sink to a DisplayPort dual mode connectivity sink/source. For example, there is no solution for connecting a dual mode connectivity sink/source device having a HDMI connector to a source/sink device with a DisplayPort connector. That is, currently there is no known technique to support complete interoperability at least between HDMI and DisplayPort multimedia interfaces.